#16276: Feature request: Polymorphic kinds in Data.Functor.Classes -------------------------------------+------------------------------------- Reporter: siddharthist | Owner: (none) Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.6.3 Keywords: polykinds | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- The classes in Data.Functor.Classes have a somewhat restrictive kind signature: {{{ *Data.Functor.Classes> :k Eq1 Eq1 :: (* -> *) -> Constraint }}} As a result, we redefine [1] many of them in the [https://hackage.haskell.org/package/parameterized-utils-1.0.1/docs/Data- Parameterized-Classes.html parameterized-utils] library. It would be quite easy to make more polymorphic (have kind "(k -> *) -> Constraint"). If everyone thinks this is a good idea, I'm happy to submit a pull request. [1]: To be precise, there are actually a few axes along which the classes in parameterized-utils vary from those in base. Some, like OrdF, require more type-level evidence. Others, like EqF, don't require their type parameter to have the corresponding instance. There are a lot of points in the design space here. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/16276 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler